In most of the programming language True and False are considered as the boolean values. But Perl does not provide the type boolean for True and False. In general, a programmer can use the term “boolean” when a function returns either True or False. Like conditional statements(if, while, etc.) will return either true or false for the scalar values.
Example:
# Perl Code to demonstrate the boolean values # variable assigned value 0 $k = 0;
# checking whether k is true or false if ( $k )
{ print "k is True\n" ;
} else { print "k is False\n" ;
} # variable assigned value 2 $m = 2;
# checking whether m is true or false if ( $m )
{ print "m is True\n" ;
} else { print "m is False\n" ;
} |
Output:
k is False m is True
True Values: Any non-zero number i.e. except zero are True values in the Perl language. String constants like ‘true’, ‘false’, ‘ ‘(string having space as the character), ’00’(2 or more 0 characters) and “0\n”(a zero followed by a newline character in string) etc. also consider true values in Perl.
- Example:
# Perl Code to demonstrate the True values # variable assigned value 5 $a = 5;
# checking whether a is true or false if ( $a )
{ print "a is True\n" ;
} else { print "a is False\n" ;
} # string variable assigned white # space character $b = ' ' ;
# checking whether b is true or false if ( $b )
{ print "b is True\n" ;
} else { print "b is False\n" ;
} # string variable assigned 'false' # value to it $c = 'false' ;
# checking whether c is true or false if ( $c )
{ print "c is True\n" ;
} else { print "c is False\n" ;
} # string variable assigned "0\n" # value to it $d = "0\n" ;
# checking whether d is true or false if ( $d )
{ print "d is True\n" ;
} else { print "d is False\n" ;
} |
Output:
a is True b is True c is True d is True
False Values: Empty string or string contains single digit 0 or undef value and zero are considered as the false values in perl.
- Example:
# Perl Code to demonstrate the False values # variable assigned value 0 $a = 0;
# checking whether a is true or false if ( $a )
{ print "a is True\n" ;
} else { print "a is False\n" ;
} # string variable assigned empty string $b = '' ;
# checking whether b is true or false if ( $b )
{ print "b is True\n" ;
} else { print "b is False\n" ;
} # string variable assigned undef $c = undef ;
# checking whether c is true or false if ( $c )
{ print "c is True\n" ;
} else { print "c is False\n" ;
} # string variable assigned "" # value to it $d = "" ;
# checking whether d is true or false if ( $d )
{ print "d is True\n" ;
} else { print "d is False\n" ;
} |
Output:
a is False b is False c is False d is False
Note: For the conditional check where the user has to compare two different variables, if they are not equal it returns False otherwise True.
- Example:
# Perl Program demonstrate the conditional check # variable initialized with string $x = "GFG" ;
# using if statement if ( $x eq "GFG" )
{ print "Return True\n" ;
} else { print "Return False\n" ;
} |
Output:
Return True